The present invention relates to game balls and in particular to such sport balls as footballs, soccer balls and the like, wherein strand materials are wound about a rubber bladder and then provided with an exterior cover. The present invention also relates to the manufacture of such game balls.
Molded game balls have been developed as a most recent substitute for the original, exclusively hand sewn game balls having covers made from individual segments, generally formed of natural leather. The manufacture of game balls to be considered for use in organized amateur and professional sports, is a time consuming task and involves an expensive method and a number of highly qualified operators to perform. In general, the method of producing molded game balls, requires the following steps: first, an inflated rubber bladder is wrapped into a reinforcing cover, made of textile segments. This textile cover, generally referred to as a "bag", is repeatedly reinforced by the application of a rubber compound which is then vulcanized. Thereafter outer cover segments, most made of leather, are adhesively bonded to vulcanized "bag". (See Czechoslovak Pat. No. 135824). Other recent methods of manufacture of molded gam balls abstain from the preparation of the so-called textile bag. According to these later methods, the inflated rubber bladder is provided with a relatively thick blanket of yarn or filament, wound about the same. (See for example U.S. Pat. No. 3,887,416 and French Pat. No. 1,488,920). These latter methods, on the one hand, provide a reinforcing effect tending to keep the game ball in its regular shape while on the other hand improve the flight characteristics of the game ball and its "bounce". The former aspect being of utmost importance in a maintaining satisfactory shape of the ball during extended play. The latter aspect is of importance in the control of the ball by the player during the game itself.
In order to achieve the aforementioned properties in the finished game ball, the precise network of yarn, wrapped in accordance with these later patents, require regular orientation in all directions around the circumference of the inflated bladder. This regular orientation must not be disturbed either during the subsequent wrapping of the yarn, or in the subsequent manufacturing steps. To effect this, it has been known to apply to the surface of the rubber bladder a layer of uncured rubber. This however does not guarantee that subsequent windings, or the subsequent handling of the ball, will allow the ball to be maintained stable since only the first layer of the winding is impressed into the layer of the uncured leather. The subsequent layers of yarn have a freedom of movement and slip over the previously deposited layers of the winding. It is only after the final vulcanization, that these yarns are bonded in place. In this connection, however, the final vulcanization has the sole effect of local stabilization of the winding yarns which might have previously been incorrectly or irregularly deposited upon the bladder surface. As a result, even after final vulcanization and binding of the yarn, the final effect in the ball is one of decreased quality.
It is the purpose of the present invention to remove the aforementioned disadvantages and to secure a regular deposition of the wound yarn about the supporting inner bladder.
It is the further object of the present invention to provide for the simultaneous local stabilization of the yarn as it is being wound. It is still another object of the present invention to provide a game ball, of the type described, which has a greater stability, more uniform quality characteristics, and a more uniform construction.
The foregoing objects together with the other objects and advantages of the present invention will be apparent from the following disclosure.